uk.org.ogsadai.activity.xmldb
Class XPathStatementActivity

java.lang.Object
  |
  +--uk.org.ogsadai.activity.Activity
        |
        +--uk.org.ogsadai.activity.xmldb.XMLDBActivity
              |
              +--uk.org.ogsadai.activity.xmldb.XPathStatementActivity

public class XPathStatementActivity

extends XMLDBActivity

An XMLDBActivity for performing XPath statements.

For information on this activity see the OGSA-DAI user doc: OGSA-DAI/doc/interaction/activities/xml/xPathStatement.html

Author:

The OGSA-DAI Project Team

Field Summary

private static java.lang.String	COPYRIGHT_NOTICE Copyright statement
private static DAILogger	LOG Logger object for logging in this class
private BlockMaker	mBlocks Used to generate the result blocks.
private java.util.Map	mNamespaceMappings The namespace mappings.
private java.lang.String	mQuery The XPath query string.
private java.lang.String	mResourceID The resource ID to query or null to query the whole collection.

Fields inherited from class uk.org.ogsadai.activity.xmldb.XMLDBActivity

mDataResource, mOutput, mSubCollectionName, mUserCredentials

Fields inherited from class uk.org.ogsadai.activity.Activity

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

XPathStatementActivity(org.w3c.dom.Element element)
Constructs an XPath activity using the specified XML element.

Method Summary

void	processBlock() Performs an iteration of the processing of an activity.
protected void	processFirst() This method is called during the first iteration of processing an activity.

Methods inherited from class uk.org.ogsadai.activity.xmldb.XMLDBActivity

initialise

Methods inherited from class uk.org.ogsadai.activity.Activity

cleanUp, connectsTo, createOutputPipe, getActivityConfiguration, getActivityName, getCause, getName, getObservableStatus, getProperties, getSession, getStatus, hasActivityConfiguration, hasProperties, process, setActivityName, setCompleted, setError

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

COPYRIGHT_NOTICE

private static final java.lang.String COPYRIGHT_NOTICE

Copyright statement

See Also:

Constant Field Values

LOG

private static DAILogger LOG

Logger object for logging in this class

mBlocks

private BlockMaker mBlocks

Used to generate the result blocks.

mQuery

private java.lang.String mQuery

The XPath query string.

mNamespaceMappings

private java.util.Map mNamespaceMappings

The namespace mappings.

mResourceID

private java.lang.String mResourceID

The resource ID to query or null to query the whole collection.

Constructor Detail

XPathStatementActivity

public XPathStatementActivity(org.w3c.dom.Element element)
                       throws ActivitySpecificationException,
                              ActivityCreationException

Constructs an XPath activity using the specified XML element.

Parameters:

element - Element to configure the activity with - from a perform document.

Throws:

ActivityCreationException - If there is a problem constructing the activity due to an implementation error or OGSA-DAI confguration problem.

ActivitySpecificationException - If there is a problem constructing the activity due to an invalid setting in element. mistake such as an invalid setting.

Method Detail

processBlock

public void processBlock()

Description copied from class: Activity

Performs an iteration of the processing of an activity. This may involve reading a block of input data and writing a block of output data, or may involve some other kind of processing. When an activity is processed by the OGSA-DAI engine, this method will be invoked repeatedly until the activity either completes or stops due to an error or termination call. An implementation of this method should invoke the setCompleted method to indicate that processing is complete, or the setError method if an error occurs that will prevent the processing from completing.

Specified by:

processBlock in class XMLDBActivity

processFirst

protected final void processFirst()

Description copied from class: Activity

This method is called during the first iteration of processing an activity. It can be overridden by subclasses to define some processing that should be done only once during the first iteration of the activity processing, for example evaluating a database query.

Overrides:

processFirst in class Activity